Combining access control and trust negotiations in an On-line Social Network

Abstract

Protection of On-line Social Networks (OSNs) resources has become a primary need since today OSNs are the hugest repository of personal information on the Web. This has resulted in the definition of some access control models tailored to the protection of OSN resources. One of the key parameter on which access control decisions in OSNs should be based is represented by the trust between OSN users. A wellknown approach for the management of trust relationships is represented by trust negotiations [1], [2]. In this paper, we show how access control and trust negotiation can be combined in a framework for the protection of OSN resources. Moreover, we show how the outcome of a trust negotiation can be exploited to dynamically adjust the trust level between OSN users.

A rule-based policy language for selective trust propagation in social networks

“…We believe that one of the fundamental parameters on which access control decisions should be based in an open environment like OSNs is represented by user trust [10]. Our starting point in this paper is the OSN access control model proposed in [3] and further developed in [1], that allows OSN users to execute trust negotiations over their data items and resources. In such model -briefly outlined in Section 3 -it is possible to define several edge types, denoting the various kinds of relationship occurring among OSN users.…”

“…A resource in the OSN can be modelled as a pair (R, AttrList), where R ∈ RN and AttrList is a set of pairs (a, v), where a ∈ AN and v ∈ Va. In what follows, given a tuple t, we denote with comp(t) the value of the component comp of tuple t. We assume that OSN resources are protected according to the model presented in [3] and extended in [1]. According to this model, access control requirements of OSN users are expressed in terms of access rules specified by resource owners.…”

“…Such relationships represent the results of past interactions between users of the OSN. The trust level associated with such newly created relationships is defined on the basis of the value of the resources exchanged during the access control protocol to satisfy the specified resource conditions [1]. Formally, a virtual relationship is an…”

“…According to this model, access control requirements of OSN users are expressed in terms of access rules specified by resource owners. Access rules are sets of both access conditions [3] and resource conditions [1], which are formally defined as follows. Access and resource conditions express different complementary constraints about the nodes of a social network, all instrumental to enforce access control.…”

“…Each OSN user uses such type of conditions to define the rules which regulate the access to the resources she/he owns. In [1], the OSN model defined in [3] has been extended by introducing the possibility for each user of the OSN to informally define local relationships called dynamic relationships 1 . Such relationships represent the results of past interactions between users of the OSN.…”